Routine
Eye Exams Help Find Glaucoma Early
New
Medications Offer Early Treatment Options
It
is called the silent thief of sight, and for good reason.
Glaucoma
has few if any early symptoms. And when they do appear, the disease
has already robbed its victims of some sight. About 3 million Americans
have glaucoma, but many do not know it yet.
Regular,
routine eye exams, including special tests, can improve the odds of
early detection, experts say. And, once detected, the disease can be
controlled - and remaining vision preserved - with improved medications
and surgery techniques.
"The
key is to get checked before the disease becomes symptomatic, " says
Dr. Andrew Iwach, an ophthalmologist at the University of California
San Francisco.
Since
glaucoma risk rises with age, eyes should be tested at about age 35
and 40, then every two to four years after age 40 and every one to two
years after age 60, suggests the Glaucoma Research Foundation.
Those at high risk due to family history should be examined every one
to two years after age 35.
Glaucoma
Causes Vision Loss
Glaucoma
is actually a group of eye diseases, but all types damage the optic
nerve, causing vision loss and, sometimes, blindness. The optic nerve
connects the retina to the brain and it houses more than 1 million nerve
fibers.
For
good vision, a person needs a healthy optic nerve.
What goes wrong in glaucoma? In the front of the eye, clear fluid flows
in and out of a space called the anterior chamber.
When
the fluid passes out too slowly and builds up, pressure can increase
and this intraocular pressure can rise to the point where it damages
the optic nerve. This form of the disease, the most common, is called
open angle glaucoma.
It
is so named because the fluid leaves the anterior chamber at the
open angle where the cornea and the iris meet.
Some
people have glaucoma, and optic nerve damage, even without the pressure
within the eye rising - a type called low-tension or normal-tension
glaucoma.
And,
in recent years, Dr. Iwach says, experts have discovered the thickness
of the cornea somehow plays a role in who gets glaucoma.
"We
may have a patient who has a higher than normal pressure, but the optic
nerve looks fine," he says. Odds are the patient has a thick cornea,
somehow possibly protecting against damage to the nerve.
During
an exam for glaucoma, physicians will also look at the optic nerve,
measure the intraocular pressure and evaluate peripheral vision - often
affected first in glaucoma.
To lower the pressure inside the eye, drops are commonly prescribed.
Newer
Treatments Give Hope
"Twenty
years ago, in order to control glaucoma, we needed to use drops four
times a day," says Dr. Michael Berlin, a professor of clinical ophthalmology
at the Jules Stein Eye Institute at the UCLA David Geffen School of
Medicine.
Some
of the newer eyedrop medications only need to be taken once or twice
a day. Drops work either by causing the eye to make less fluid or helping
the fluid drain.
If
surgery is deemed the best treatment, a physician may perform
a procedure called a laser trabeculoplasty. This procedure involves
a laser aimed at the lens of the eye and makes several evenly spaced
burns, stretching the drainage holes inside the eye and allowing the
fluid to drain more effectively.
While
the traditional approach has been to use medications first, then surgery
if the glaucoma still progresses, Dr. Iwach says the latest thinking
has it that some patients may benefit most from having surgery first.
Compliance
with medication is a problem among patients, Drs. Berlin and Iwach agree.
"Most
patients are not compliant," Dr. Berlin says. Part of the reason, he
suspects, is the patient can tell little difference in vision during
the short term, whether he takes the medicine or not.
Good
patient-physician communication is the key. All the latest information
- whether medication or laser therapy is best; which eye drops are preferred
- "has to be customized to the individual patient," Dr. Iwach says.
Always
consult your physician for more information.
Online
Resources
American
Academy of Ophthalmology
Centers
for Disease Control and Prevention (CDC)
Glaucoma
Research Foundation
National
Eye Institute
National
Institutes of Health (NIH)
Prevent
Blindness America
US
Department of Heath and Human Services
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